1. Field of the Invention
This application relates to pipeline cleaning devices. More particularly, it concerns devices for removing from the inside wall of large diameter, cylindrical pipelines barnacles, mussels, oysters, algae and like marine growths or any other deposits that impede liquid flow through the pipelines.
2. Description of the Prior Art
Large diameter, cylindrical pipelines that transport water containing (a) marine life that become attached and grow on the inside surface, and/or (b) salts or other materials that may form crusts on such surface that impede liquid flow exist in many different environments, e.g., electric power plant water intake pipes, wastewater plant effluent discharge pipes, etc. Such flow impediment deposits must be periodically removed to restore the liquid flow capacity of such pipelines to acceptable levels.
One method of removal of such pipeline deposits has been to send scuba divers equipped with hand operated tools into the pipeline to chip and scrape the deposits from the pipeline inner wall. Such cleaning methods are highly labor intensive and generally require shutdown of the pipeline during the cleaning operation.
Another method of removal of large pipeline deposits involves use of hydraulic operated hull cleaners by scuba divers. However, the use of this type equipment on inside curved surfaces is very hazardous, time consuming and costly.
A further prior deposit removal method involves the use of high pressure (10,000 psi) water jets on what is known in the trade as a jet sled with one rotor propelled by a water pump and pulled through the pipeline by cables or tug boat. Support equipment for this is very expensive including a heavy lift crane, large pumps and winches.
Yet another prior deposit removal method involves a device called a pig which, for large diameter pipes, may weigh up to 40,000 lbs. The pig is pushed through the pipe by low pressure, high volume water. It has scrapers that horizontally scrape the deposits off the walls. Heavy duty support equipment and much manpower is needed to carry out this method and the operation is very expensive.
A need exists for improving the removal of solid deposits from the inside surface of large diameter, cylindrical pipelines by providing new, more efficient machines for carrying out such operations and reducing the use of manual labor and costs in performing such cleaning operations.